Other mistake: The body of a man is dropped from a plane into the sea with fake documents to mislead Germans. To convince the enemy that he's a soldier, cause of death needs to pass for drowning. The first drowned corpse viewed has no legs, so Firth keeps looking. He's told that a man who took rat poison to end his life is a good fit since the poison is undetectable. However, no mention is made of the fact that there is no sea water in his lungs - something any coroner would discover. (01:43:40)
Suggested correction: It is a fallacy that drowned people have seawater-filled lungs; usually, there will be a little seawater, which then irritates the lungs, causing inflammation and fluid buildup (pulmonary oedema), which dilutes any seawater traces. Also, by the way, one of the symptoms of phosphine poisoning (I believe the poison he took) is also pulmonary oedema. So it is understandable for one of the UK's top pathologists to choose this man as a possible subject.
Suggested correction: Historical fact not a movie mistake! Operation Mincemeat - British intelligence obtained the body of Glyndwr Michael, who killed himself with rat poison, dressed him as an officer of the Royal Marines and placed items on him identifying him as Captain William Martin. They put letters on him strongly hinting that the Allies were going to invade Greece and Sardinia instead of Sicily. His body was set adrift off the coast of Spain, knowing it would be washed ashore. The film gets all this right.
